As awareness about the environment and global warming raises, the reduction of energy consumption (especially in the construction industry) has attracted much attention. According to IEA statistics, global energy consumption is about 8428 Mtoe, with buildings consuming the most energy (about 33%). Lowering the indoor temperature in summer and raising the indoor temperature in winter in ways that reduce the amount of energy consumed by air conditioning units is an important topic, especially as regards buildings constructed largely of metal building materials, which can have a high thermal conductivity (k=30 W/m·K to 237 W/m·K) Reducing the thermal conductivity of the metal building material can help to reduce the transfer of heat from outdoors to indoors in summer, and help to prevent warm air from being transferred from indoors to outdoors in winter, thereby saving energy.
Conventional thermal insulation coating materials have limited energy-saving effects due to their high thermal conductivity (k=0.15 W/m·K to 0.3 W/m·K). High efficient thermal insulation materials (e.g. aerosol) may have a thermal conductivity of 0.01 W/m·K, but they cannot be continuously coated on metal building materials and chalking. In other words, highly efficient thermal insulation materials with a high cost and low bending endurance are difficult to process, and cannot be applied on building materials. Mesoporous thermal insulation materials have a lower thermal conductivity (0.017 W/m·K to 0.2 W/m·K) and can be applied in metal coating process. However, mesoporous thermal insulation materials are based on oxide of tetraethoxysilane, have a poor bending endurance after being sintered, and cannot be continuously coated. Accordingly, a thermal insulation building material is called for to meet the requirements of low thermal conductivity, low cost, flexibility, and continuous coatability.